I wanted too much too quickly, by setting the metronome to +5 every 8 bars playing the beat till I completely lose track. It´s a good test to know, where I am at … but I will not gain anything in that way. To improve in speed, I should practice at the level I am now comfortable with – and not squeeze hard and get messy. Now I increase the tempo manually, in slight increments, and only if I feel comfortable. It´s more like: If I get bored at this speed, then I go faster.